[roll] Roll fuchsia [fidlcat] Replace <regex> and <regex.h> with re2::RE2

See RFC-0105 for background:
https://fuchsia.dev/fuchsia-src/contribute/governance/rfcs/0105_regular_expression_libraries

For the most part this is purely mechanical, with a few exceptions:

- By default, RE2 does not match against invalid UTF8. If the source
  strings may be invalid UTF8 (e.g., if they can contain '\0'), the RE2
  object must be created in Latin1 mode.

- RE2 is not copyable or movable. Where a regexp needs to be moved, the
  RE2 object has been wrapped with std::unique_ptr.

- RE2 has an option to use "POSIX egrep syntax", which is equivalent to
  <regex.h>'s regcomp with the REG_EXTENDED flag. I decided not to use
  RE2's POSIX option for two reasons:

  1. For regexps built from static regexp literals, I verified that
     RE2's default syntax is sufficient to parse those static literals.

  2. For regexps that come from user input, I think we should explicitly
     choose RE2 syntax over POSIX syntax for consistency across Fuchsia.
     Tools written in other languages (Go and Rust) already use RE2
     syntax -- using RE2 syntax in C++ tools will provide a more unified
     interface. See RFC-0105 for further discussion.

Note: the above comments apply generally to the transition from <regex>
and <regex.h> to RE2; some comments may not apply to this specific CL.

Original-Bug: 77811
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/676253
Original-Revision: 8edbc86da4320a16b4523724b7998cd8440b311e
GitOrigin-RevId: 8ef8468ad989513c97a28fe8291a0a274092e831
Change-Id: I085c09c58924d3551ee58fe488185f2cbf4e3cfe